Seaweed biogeochemistry: Global assessment of C:N and C:P ratios and implications for ocean afforestation
Seaweed biogeochemistry: Global assessment of C:N and C:P ratios and implications for ocean afforestation
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DOI：
10.1111/jpy.13381
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发表时间：
2023-08-19
影响因子：
2.9
通讯作者：
Bach，Lennart T.
中科院分区：
文献类型：
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作者：
Sheppard，Emily J.;Hurd，Catriona L.;Bach，Lennart T.
藻类的碳-氮（C：N）和碳-磷（C：P）比是了解许多海洋生物地球化学过程的基础，如营养盐通量和气候调节。我们综合了文献数据（444个物种，> 400个地点），并从澳大利亚塔斯马尼亚岛收集了原始样本（51个物种，10个地点），以更新全球海藻碳氮比（C：N）和碳氮比（C：P）。更新后的海藻C：N的全球平均摩尔比为20（从6到123不等），C：P为801（从76到4102不等）。C：N和C：P比值受海水无机营养盐浓度和季节性的显著影响。此外，C：N比率因门而异。褐色海藻（褐藻门，褐藻纲）的平均C：N最高，为27.5（范围：7.6 - 122.5），其次是绿色海藻（绿藻门），为17.8（6.2 - 54.3），红色海藻（红藻门），为14.8（5.6 - 77.6）。我们使用更新的C：N和C：P值比较海藻组织化学计量与最近报道的浮游生物群落化学计量值。我们的研究结果表明，海藻平均有2.8和4.0倍高的C：N和C：P比浮游植物，表明海藻可以吸收更多的碳在其生物量为一定量的营养资源。本文提出的化学计量比较是关于海洋造林（用海藻故意取代浮游植物以增强海洋生物碳汇）的讨论的核心，有助于理解大规模海藻养殖下浮游植物对海藻的营养重新分配的影响。
Algal carbon‐to‐nitrogen (C:N) and carbon‐to‐phosphorus (C:P) ratios are fundamental for understanding many oceanic biogeochemical processes, such as nutrient flux and climate regulation. We synthesized literature data (444 species, >400 locations) and collected original samples from Tasmania, Australia (51 species, 10 locations) to update the global ratios of seaweed carbon‐to‐nitrogen (C:N) and carbon‐to‐phosphorus (C:P). The updated global mean molar ratio for seaweed C:N is 20 (ranging from 6 to 123) and for C:P is 801 (ranging from 76 to 4102). The C:N and C:P ratios were significantly influenced by seawater inorganic nutrient concentrations and seasonality. Additionally, C:N ratios varied by phyla. Brown seaweeds (Ochrophyta, Phaeophyceae) had the highest mean C:N of 27.5 (range: 7.6–122.5), followed by green seaweeds (Chlorophyta) of 17.8 (6.2–54.3) and red seaweeds (Rhodophyta) of 14.8 (5.6–77.6). We used the updated C:N and C:P values to compare seaweed tissue stoichiometry with the most recently reported values for plankton community stoichiometry. Our results show that seaweeds have on average 2.8 and 4.0 times higher C:N and C:P than phytoplankton, indicating seaweeds can assimilate more carbon in their biomass for a given amount of nutrient resource. The stoichiometric comparison presented herein is central to the discourse on ocean afforestation (the deliberate replacement of phytoplankton with seaweeds to enhance the ocean biological carbon sink) by contributing to the understanding of the impact of nutrient reallocation from phytoplankton to seaweeds under large‐scale seaweed cultivation.